JPS63134665A - Gas scavenger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The invention relates to the extraction of gases from semiconductor wafers as they exit a processing chamber in a vertical or horizontal chemical furnace (m
dxct).

(Prior Art) During semiconductor manufacturing processes such as diffusion, deposition, abrasion, and annealing, semiconductor wafers in a boat-shaped container are heated in a horizontal tubular chamber surrounded by electrical heating elements. treated with toxic, flammable or corrosive gases. A gas scavenger is used at the exhaust end of the tubular chamber to draw gas into the exhaust mechanism chamber. FIG. 1 is a cross-sectional plan view of a conventional heated wall fabricated tube 24 in a furnace 23 and a scavenger 30 secured to the exhaust end 26 of the furnace. The gas flows into the supply end 25 of the processing tube 24 and through the exhaust end 26 to the scavenger 30 and further into the exhaust port 32 connected to the exhaust mechanism chamber 33.

The air is also normally exposed at the outer end surface 834 of the scavenger, which is uncovered.
The air enters the scavenger 30 and further passes through the exhaust port 32 and enters the exhaust mechanism chamber 33. Such scavengers are generally about 12 inches square to about 15 inches square in diameter; ．．
It is built to a depth of up to 723°C (approximately 18 inches).

(Problems to be solved by the invention) After processing and processing gas (process g (Lll)
Alternatively, while the purifying gas Cp1Lrrta gas> is flowing, the boat-shaped container 22 carrying the wafers is pulled out from the processing pipe 24 via the exhaust end to the scavenger 30 by a container carrier (not shown) and removed in the air. station (not shown). As shown in FIG. flows to

As a result, the particles captured in the scavenger 30 are transferred to the processing pipe 2.
Entrained in the gas shell along with entrained particles from 4, the gas is deposited on the surface of the wafer 20 as the gas passes through the vessel. Furthermore, air flow 36 is drawn across the travel path of container 22 as well.

(Effect of the invention) In the gas scavenger of the present invention, gas and air flow through the scavenger without passing through the travel path of the container.In this improved scavenger, gas and air flow through the scavenger. The peripheral wall of the scavenger, further away from the center of the filling chamber of the scavenger, and even the exhaust mechanism chamber 3.
It flows to 3. Moreover, the gas scavenger of the present invention more effectively draws processing gas and purification gas into the exhaust mechanism chamber, so that the processing pipe can operate while the atmosphere around the processing pipe remains safe.

SUMMARY OF THE INVENTION Improved scavengers generally include peripheral walls defining opposed plenum chambers at one end of which the gas flow is directed into a vertical or horizontal furnace. It communicates with the processing chamber and the other end with the atmosphere.

The outer wall is also provided with a gas exhaust port through which the gas flow communicates with the gas exhaust mechanism chamber. The air-filled chamber is divided by an inner wall into a back chamber in which the wafer travels and a second chamber in which the gas flow communicates with a gas exhaust port provided in the outer wall. The inner wall may be provided with windows for extracting gas and air flowing into the first chamber around the wafer path into the second chamber. Preferably, the air substantially surrounds the travel path of the wafer so that substantially no air smear crosses the surface of the wafer, and most preferably, no air crosses the surface of the wafer.

The details of the scavenger will be explained below, and as will be explained later, both ends of the second chamber defined by the outer wall and the inner wall are sealed to prevent gas short-circuiting at both ends of the plenum chamber. It is preferable. It is also preferred that the scavenger include a damper in operative relationship with the windowed inner wall to control the gas flow rate and velocity without changing the air flow pattern.

EXAMPLES AND OPERATIONS In the following, preferred embodiments of the invention will be described to reveal other details, objects and advantages of the invention.

2 and 3, the main structure of an improved scavenger intended for use with a horizontal process tube 40 having a feed end 42 and an exhaust 1444 is illustrated. Such processed pipe 4
0 usually dies when two to four similar lightning strikes are stacked in the furnace 46.

Scavenger 50 comprises an outer circumferential wall 52 forming a cylinder 54 having a plenum 54 , an inner end 56 and an outer end 58 . A conventional flange 60 defining a circumference of a circle 63 that matches the outside diameter of the plenum chamber 54 is typically welded to the outer wall 52 and adapted to be secured to the furnace. The gas flow is between the inner end 56 of the scavenger 50 and the exhaust end 44 of the processing tube 40.
Alternatively, as shown in FIG. 3, the exhaust end 44 of the processing tube 40 may project substantially into the plenum chamber. An exhaust gas port 61 is provided on the outer wall 52 of the scavenger 50 and communicates with an exhaust mechanism chamber 62.

The scavenger 50 has an inner wall 70 provided with a window spaced apart from the outer wall 52, and the air-filled chamber is connected to the container 2 on which the wafers are placed.
2 runs between the processing pipe 40 and the attachment/detachment station (not shown). d80 and a second chamber 82 generally defined by an inner wall 70 and an outer wall 52. A flange 72 defining a circle 78 of the same diameter and alignment as the central chamber 80 may be welded to the outer end of the inner wall 70 . End plate 6
0 and 72 are used to prevent processing gas from leaking into the atmosphere.
It is preferable to seal both ends of 2.

A window 76 provided in the inner wall 70 allows the gas to flow between the central chamber 80 and the second chamber of the plenum chamber 54 in communication with each other. Preferably, windows 76 enclose the central chamber such that the gas and air flow paths are directed radially outward rather than across the wafer 20 toward the center of the central chamber. The windows can be spaced closer together at locations farther away from the exhaust port 61 in order to balance the flow rate and pressure drop of the gas and air flowing into the second chamber.

A damper 90 equipped with a window of the same shape as the window 76 of the inner wall 70 and slidably inserted into the central chamber 80;
-I3 SQ 5 of effective face-to-face examination of 6. '/: The self-effective pressure drop between the gas and the exhaust mechanism chamber on the one hand and the exhaust mechanism chamber on the other is relatively low. Windows 7 if required
Preferably, the effective area of 6 is expanded.

Scavengers, such as those illustrated in FIGS. 2 and 3, are generally constructed from sheet stainless steel, preferably electropolished to a high gloss finish. The diameter of the inner wall 70 of the scavenger is approximately 38 mm. lOcm (approximately 15 inches), and the diameter of the outer wall 52 is approximately 40.64 cm (approximately 16 inches).

A second inventive embodiment, illustrated in FIG. 4, has a rectangular cross section. In this scavenger 90, the central chamber 9
2 and a second chamber 94 are divided by an inner wall 96 provided with an opening. Such an embodiment is used in conjunction with a container having a semi-cylindrical shell-like bottom surface that generally prevents gases flowing underneath the container from passing through the wafers in the container.

Although preferred embodiments of the invention have been shown and described, the invention is not limited to these embodiments, but may be embodied in other ways within the scope of the following claims.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional plan view of a conventional scavenger (as described above). FIG. 2 is an exploded side perspective view of the preferred embodiment of the invention. FIG. 3 is a cross-sectional plan view of the scavenger 3-3 in FIG. 2. FIG. 4 is a schematic front perspective view of the second embodiment of the invention. 20... Semiconductor wafer 40... Processing chamber 50.
...Gas scavenger 52...Outer peripheral wall 54...Light scavenging chamber 56...Inside end of charging chamber 58...Outside end of charging chamber 61...Gas exhaust port 62...Gas exhaust mechanism 70...Inner wall 76...Window
80...1st room 82...Rin 14
90... Dannogu (3 other people)

Claims (8)

[Claims] (1) In a gas scavenger that extracts gas from a semiconductor wafer as it exits the processing chamber along a passageway, the gas flow communicates with the processing chamber at one end and at a second end. an outer circumferential wall defining a plenum with opposing ends in communication with the atmosphere and having a gas exhaust port through which a flow of gas communicates with the gas exhaust mechanism chamber; The chamber is divided into a first chamber in which the wafer travels and a second chamber in which the gas flow communicates with the exhaust port in the outer peripheral wall, and the inner wall includes a plurality of windows around the wafer travel path. Characteristic gas scavenger. (2) The gas scavenger according to claim 1, further comprising a damper in operative relationship with the inner wall provided with the window. (3) The gas scavenger according to claim 2, wherein the damper is slidable. (4) The gas scavenger according to claim 2, wherein the damper is rotatable. (5) The gas scavenger according to claim 1, wherein the inner wall provided with the window is installed at a distance from the outer wall. (6) The gas scavenger according to claim 1, wherein both ends of the second chamber defined by the inner wall and the outer wall are sealed. (7) The gas scavenger according to claim 1, wherein the window provided in the inner wall substantially surrounds the wafer travel path. (8) The total area of the windows provided in the inner wall is larger than the cross-sectional area of the end of the second chamber through which the semiconductor wafer exits through the covered exit.
Gas scavenger as described in section.